Deregulated matriptase activity in oral squamous cell carcinoma promotes the infiltration of cancer‐associated fibroblasts by paracrine activation of protease‐activated receptor 2

Abstract

Cancer-associated fibroblasts (CAFs) are known to contribute to cancer progression. We have reported that cell surface expression of hepatocyte growth factor activator inhibitor 1 (HAI-1) is decreased in invasive oral squamous cell carcinoma (OSCC) cells. This study examined if HAI-1-insufficiency contributes to CAF recruitment in OSCC. Serum-free conditioned medium (SFCM) from a human OSCC line (SAS) stimulated the migration of 3 human fibroblast cell lines, NB1RGB, MRC5 and KD. SFCM from HAI-1-knockdown SAS showed an additive effect on the migration of NB1RGB and MRC5, but not KD. SAS SFCM induced protease-activated receptor-2 (PAR-2) expression in NB1RGB and MRC5, but not in KD, and a PAR-2 antagonist blocked the stimulatory effect of HAI-1 knockdown on migration of the PAR-2 expressing cell lines. Moreover, HAI-1-deficient SFCM showed additive stimulatory effects on the migration of wild-type but not PAR-2-deficient mouse fibroblasts. Therefore, the enhanced migration induced by HAI-1-insufficiency was mediated by PAR-2 activation in fibroblasts. This activation resulted from the deregulation of the activity of matriptase, a PAR-2 agonist protease. HAI-1 may thus prevent CAF recruitment to OSCC by controlling matriptase activity. When HAI-1 expression is reduced on OSCC, matriptase may contribute to CAF accumulation by paracrine activation of fibroblast PAR-2. Immunohistochemical analysis of resected OSCC revealed increased PAR2-positive CAFs in 35% (33/95) of the cases studied. The increased PAR-2 positive CAFs tended to correlate with infiltrative histology of the invasion front and shorter disease-free survival of the patients.

Hepatocyte growth factor activator inhibitors (HAI‐1 and HAI‐2): Emerging key players in epithelial integrity and cancer

“…This phenomenon is mediated by MET‐AKT‐mTOR signaling initiated by matriptase‐mediated proHGF/SF activation and Gαi‐NFκB signaling induced by matriptase‐mediated activation of PAR‐2 in keratinocyte stem cells . Moreover, matriptase confers progression of established squamous cell carcinomas by recruitment of cancer‐associated fibroblasts through activation of fibroblast PAR‐2 . In accordance with these observations, high matriptase levels in head and neck squamous cell carcinoma predict poorer prognosis of the patients …”

Protease‐activated receptor‐2 accelerates intestinal tumor formation through activation of nuclear factor‐κB signaling and tumor angiogenesis in ApcMin/+ mice

“…Transfection was carried out using Lipofectamine RNAiMax reagent (Invitrogen) followed by cultivation in DMEM supplemented with 10% FBS for 24 hours. The cells were treated with or without 10 µmol/L PAR‐2 agonist, Ser‐Leu‐Ile‐Gly‐Arg (SLIGR)‐NH 2 , or 10 µmol/L PAR‐2 selective antagonist, Phe‐Ser‐Leu‐Leu‐Arg‐Tyr (FSLLRY)‐NH 2 (Peptides International) …”

“…Protease‐activated receptor‐2 is expressed not only in epithelial cells but also leukocytes, endothelial cells, and smooth muscle cells . Although PAR‐2 is hardly detectable in normal fibroblasts, activated fibroblasts express PAR‐2, as do cancer‐associated fibroblasts . Protease‐activated receptor‐2 is also expressed by most cancer cells of epithelial origin, including colorectal cancer cells .…”

Membrane-Anchored Serine Proteases and Protease-Activated Receptor-2–Mediated Signaling: Co-Conspirators in Cancer Progression

“…Recent studies also suggest that matriptase can function in a paracrine manner to activate PAR-2 (100). Pericellular matriptase activity on the surface of oral SCC, caused by insufficient HAI-1, was shown to activate PAR-2 on the surface of cancer-associated fibroblasts (CAF), leading to enhanced CAF migration and infiltration (100).…”